Operating Instructions Part 2

28 OEM Series™ I/O Guide MDS 05-3624A01, Rev. B
The RTU simulator (MDS Part No. 03-2094A01) is a microcontroller
that emulates a remote terminal unit operating at 1200, 2400, 4800, or
9600 bps. Custom software is supplied with the RTU simulator that
allows continuous polling of remote radios using an IBM-compatible
personal computer. The software reports the number of polls sent, polls
received, and the number of errors detected.
NOTE: It is very important to use attenuation between all units in the
test setup. The amount of attenuation required depends on the
number of units being tested and the desired signal strength
(RSSI) at each transceiver during the test.
A maximum level of -50 dBm is recommended at each
transceiver, because the radio’s RSSI reporting will not be
accurate above this level. In no case should a signal stronger
than +10 dBm be applied to any transceiver in the test setup,
or damage may result.
Invisible place holder
Figure 13. Typical setup for bench testing of radios
6.3 Helical Filter Adjustment
If the operating frequency of the radio is changed more than 10 MHz,
the helical filters should be adjusted for maximum received signal
strength (RSSI). If adjustment is required, follow these steps:
1. For enclosed units, remove the top cover from the transceiver by
loosening the eight screws and lifting straight up.
2. Carefully remove the shield cover from the PC board.
3. Locate the helical filters. See Figure 14.
MASTER STATION
COMPUTER RUNNING MDS
POLL.EXE PROGRAM
REMOTE
RADIO
REMOTE
RADIO
REMOTE
RADIO
REMOTE
RADIO
NON-RADIATING ATTENUATOR
• Install on any unused divider ports
• 2W minimum rating
POWER DIVIDER
POWER ATTENUATORS
• Fixed or adjustable
• 2W minimum rating
RTU SIMULATORS
(SEE TEXT)